| Summary: | 博士 === 國立中興大學 === 土木工程學系所 === 107 === The study adopts the silting rivers and the representative river treatment in Taiwan. According to the previous researches, tests in the study don’t distinguish between coarse and fine aggregates. The mixing amount of the material is tested by the weight ratio method. The effect of cement content ratio on the strength of mixing specimens is discussed. Using debris of Chichi Weir discovers the optimized rate between sand content and water-cement ratio.
The test results show that the cement content is the main factor. As the cement content ratio increases, the compressive strength also heightens. The high sand content specimens which wanted to achieve the high compressive strength, the water-cement ratio should be increased. For example, debris in Chichi Weir has a optimized ratio, the amount of the sand content is about 40-50%, the used cement content is about 7.7% (weight ratio 1:12), water-cement ratio is 1 to 1.5, and 28-day age compressive strength achieved of 70 kgf/cm2. In this study, the specimens strength distinguish between two types. Type I (basic) is designed strength of 70 kgf/cm2. Type II (ground improvement) is designed strength of 30 kgf/cm2.
Through the investigation of the upper and lower river in Wujie Dam, the riverbed of Choushui River is rising and the flow path of river is unstable after the completion of the Wujie Dam. So the highland and lowland beaches are often destroyed. Private land and agricultural land are inundated as well. Upon considering regional traffic, funding, etc., the in-situ mixing method will gradually recover the lost land, and this efficient method can also achieve partial adjustment of the flow path and protection of the beach. It is recommended to complete the river revetment in FaJhih , Wanfeng, Cinai and Chunyang Village step by step.
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